1. Field of the Invention
The present invention relates generally to cutting blades for shredders. Specifically, this invention teaches cutting blades and a rotary cutting assembly which reduce the power needed to shred paper, plastic, and other forms of media that hold information.
2. Background Information
With increased privacy concerns, shredders have become an integral part in both homes and businesses. Though originally used to destroy paper products, shredders are now used to shred other forms of media that hold information, such as compact discs. In addition, credit cards and other plastic products are commonly shredded.
Conventional shredders use a plurality of cutting blades spaced apart along a rotary shaft to form a rotary cutting assembly. Articles are shredded when fed through two parallel and opposite rotating rotary cutting assemblies.
The first common conventional shredder, called the strip-cut shredder, cut paper into strips along the entire length of the paper. A drawback with this type of shredder is that the strips can be pieced together like a puzzle.
In order to decrease this likelihood, shredder manufacturers developed the cross-cut shredder which shreds paper into tiny rectangles. This is accomplished by again having two parallel and opposite rotating rotary cutting assemblies. Cutting blades are again spaced apart along the length of each rotary shaft. When paper is fed through the two rotary cutting assemblies, it is cut in a similar fashion as the strip cut shredder. However, the cutting blades also have teeth protruding from the blade which puncture the strips into small rectangles, for example into 4 mm×40 mm pieces.
The teeth of each cutting blade are offset in the longitudinal direction of the rotary shaft such that they form a helix around the rotary shaft. The teeth are offset in order to decrease the amount of power needed to cut the paper. If the teeth were aligned in a row, then they would punch the paper at the same time, thus requiring a more powerful motor to simultaneously punch through the paper.
The Diamond Cut shredder was the next innovation in shredders. Through the use of a unique and novel rotary cutting assembly utilizing round undulating blades, Diamond Cut shredders, are able to shred paper in a diamond shape, thus offering maximum security.
Irrespective of the type of cut, shredders may be generally categorized according to the maximum number of sheets that it can shred. For example, a 10 sheet cross-cut shredder is designed to shred a maximum of 10 sheets. A 16 sheet cross-cut shredder is designed to shred a maximum of 16 sheets. Logically, the size of the shredder motor increases as the maximum number of sheets that the shredder can shred increases. More powerful motors are needed to shred greater amounts of paper, and are heavier and use more energy than the motors requiring less torque.
In order to save energy and reduce the size of the motor currently employed in shredders, the present invention seeks to employ various cutting blades and configurations which more readily shred paper thus reducing the size of the motor and saving energy.
One preferred embodiment of the claimed invention provides this by adding an additional cutting blade between the two cutting blades that are typically employed in a cross-cut shredder. The additional cutting blade has a spear shaped tooth which, in conjunction with two adjacent teeth, more readily tears through and shreds the paper. From the preceding descriptions, it is apparent that the devices currently being used have significant disadvantages and/or limitations. Thus, important aspects of the technology used in the field of invention remain amenable to useful refinement.